Composition for and method of sizing yarns



Patented Nov. 4, 1952 COMPOSITION FOR AND METHOD OF SIZING YARNS I ElmerH. Rossin, Melrose, Mass., assignor to,

Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware NoDrawing. Application August 30, 1950, Serial No. 182,399

: Thepresent invention relates to improvements in'the art of sizingwater-insoluble synthetic linear polymer warp yarns such as syntheticlinear polyamide warp yarns. It more particularly relates toimprovements in the art of sizin polyhexamethylene-adipamide warp yarnsand polyacrylonitrile warp yarns.

One of the difficulties heretofore experienced in the weaving ofsynthetic linear polymer yarns as, for example,polyhexamethylene-adipamide yarns and similar yarns, which stretch underslight stress and regain their original length quickly when the stressis removed, is that the size tends to dust or shed from the yarns duringthe weaving operation due to poor adhesion of the size with the resultthat the yarns ar not adequately protected during weaving. NaturalSizing agents such as starch or gelatin which are generally suitable forsizing cotton and regenerated cellulose yarns are not satisfactory forsizing synthetic linear polymer yarns such aspolyhexamethylene-adipamide yarns.

Various water-soluble artificial polymeric materials as, for example,polyvinyl alcohol have been suggested for sizing synthetic polymer yarnsbut these'generally are only satisfactory for sizing low twist knittingyarns. Polymethacrylic acid has been suggested heretofore as a size forpolyhexamethylene-adipamide yarns but has the disadvantages of beingdifiicultly soluble in water and also quite expensive. Also solutions ofpolymethacrylic acid are acidic and'this makes them unsatisfactory fromthe standpoint of corrosion of the machinery used in sizing and weavingthe yarns.

It has also been proposed heretofore to employ water solutions ofquaternary ammonium hydroxide salts of styrene-maleic anhydridecopolymers together with a reactive substance such as formaldehyde,alkylene polyamines or thermosetting resins for the treatment of nylonfabrics and other nylon textile materials for the purpose of producing awater resistant, permanently stiffened finish on the fabric. Thesequaternary ammonium hydroxide salts as a class are not satisfactory forsizing nylon textiles and they have only been useful when used inconjunction with the aforementioned reactive materials, namely,formaldehyde or' the like. The use of a reactive substancewith suchsalts, however, results in the formation of a water-insoluble resinwhich cannot be removed from the fabric by simple washing.

In accordance with the present invention, it ispossible to sizelinearpolymer .yarns with a a 17 Claims. (o1. 26029.6)

new essentially neutral, water-soluble polymeric material which providessized yarns having high weaving efiiciency. and. excellent, abrasionresist!- ance. t

It is accordingly one object of this invention to provide a novelcomposition for sizing water-insoluble synthetic linear polymer yarns.

A further object of this invention is to provide an improved method ofsizing water-insoluble synthetic linear polymer yarns of the nature ofsynthetic linear 'polyamide yarns and polyacrylonitrile yarns.

A further object of this invention is to provide sized water-insolublesynthetic linear polymer yarns which are produced at relatively low costand have a high weaving efiiciency when woven in customary loomsundernormal conditions of humidity.

Still further objects and advantages of this invention will appear inthe following description and the appended claims.

The objects of this invention are attained, in general, by firstapplying to the naked or presizedwater-insoluble synthetic linearpolymer yarn as, for example, a polyhexamethyleneadipamide yarn, a watersolution of a water-soluble choline salt'of' a copolymer consisting ofthe copolymerization product of an ethylene 11,5 dicarboxylic anhydrideor acid, or partial alkyl esters of such acid having not more than 3carbon atoms in the alkyl group, or combinations thereof, and apolymerizable vinylaromatic compound having a single C=CH2 group as, forexample, styrene. The solution of the choline salt of the copolymer maybe slightly acid or alkaline, but, preferably, should have a pH between4.5 and 9.5. The temperature of the size solution is generally withinthe rang of to 205 F., but preferably is within the range of to F. Afterthe solution has been applied to the synthetic polymer yarn in asuitable manner as, for example, by passing the Warp yarns'through aconventional size box containing the sizing solution, the sized yarnsare dried to render them substantially nontacky, preferably by passingthem over heated drying cans of the type conventionally employe in warpslashing machinery.

The amount of choline salt of thecopolymer applied to the yarn will varyto some extent depending upon the construction of the yarn and theamount of twist put in the yarn as Well as the construction of thefabric, but i generally within the range of about 1 to 15% by weightbased on the weight of the yarn. Best results are obtained --by applyingbetween 5 and 15% by weight of the choline salt of the copolymer basedon the yarn and such amounts are preferred.

The term water-insoluble synthetic polymer yarn as used herein isintended to includ the Water-insoluble synthetic linear polyamide yarnswhich show orientation along the fiber axis by characteristic X-raydiffraction patterns. As examples of such synthetic linear polyamideyarns may b mentioned pclyhexamethylene-adipamide yarns andpolyhexamethylenesebacamide yarns, these being preferred in thisparticular class .of synthetic polymer yarns. Other Water-insolublesynthetic linear polyamide yarnsxwhich are "also satisfactorily sized inaccordance with the methods of this invention are described in U. S.Patents Nos. 2,071,250, 2,130,523 and 2,130,948.

The term water-insoluble synthetic polymer yarns as used herein is alsointended to include yarns prepared from copolymers of vinyl chloride andvinyl acetate, polyvinylidene chloride, copolymen; of vinylidenechloride and vinyl chloride, and. pfllyfiic fylonitrile which maycontain up to 20% of a comonomer or other modifying agent, but. isnotintended to include yarns prepared from na ural polymers such ascellulose or cellulose derivatives. Of the synthetic polymer yarnsdescribed immediately above, those prepared from polyacrylonitrile ormodified-polyacrylonitrile are preferably sized in accordance with themethods of this invention.

The term yarns as used herein is intended to include monoor.multi-filament continuous filaments, or threads or yarns containingsubstantial amounts, that is, from 75 to 100% of staple fibers of thepolymers hereinbefore described.

The synthetic polymer "yarns which are sized inaccordance with themethods of this invention have :a tough elastic and smoothcoating-thereon which coating does not substantially dust-or shed fromtheyarns when the;yarnsare subsequently woven "in a loom at 5,0 to 80%relative humidity. Woven fabrics prepared frcm'the sized yarns aresubstantially free of defects normally attributable to poor sizing perse. The weaving efflciency of'the sized yarns of this invention is veryhigh andthe number ofyarns breaks-attributable to poor sizing is reducedto a minimum. Moreover, the size is readily removed from the yarns orthe woven fabric by washing the sized materialin warm 'water'or in warmwater containing synthetic detergents.

The water-soluble cholinesalt sizing agents of this invention may beprepared in various ways. In general, they are prepared by first forminga copolymeric material by the conjoint polymerization of a polymerizablevinyl aromatic compound having a single C=CH2 group as, for example,styrene, and an ethylene t e dicarboXylic acidsuch as maleic acid, or ananhydride of such acid such as maleic anhydri-d-e, or alkyl acid estersof such acid, for example, methyl acid maleate or mixtures of suchcompounds. The vinyl aromatic compound and the dicarboxylic compound orcompounds are copolymerized in a mol ratio between 1-21 and :2:1 andpreferably, in a mole ratio of 1:1 to 1.511. Althoughvarious ratios ofmonomers maybe used to prepare the copolymer within the range describedabove, the

copolymer will normally contain the vinyl .conrpoundand the dicarboxyliccompound combined in substantially equi-mclecular proportions. Theresulting copolymer is then reacted in water with choline to iorm "thecholine salt, using an amountof cholinesufiicient to dissolve the copolymer in the water, and preferably to provide a solution having a pHbetween 4.5 and 9.5. The solutions which are slightly acidic, that is,between a pH of about 4.5 and 7.0 are highly viscous and decrease inviscosity as the pH is increased. .The solutions which are alkalinereacting generally have a relativelylow'viscosityand decrease inviscosity with an increase in pH. In order to bring about a rapidreaction between the choline and the oopolymer it is preferred to heatthe water in which the reaction is carried out to a temperature of 70 to100 C.

The copolymers employed in preparing the choline salt for sizingpurposes are suitably produced by mass "polymerizing the vinyl aromaticcompound and the dicarboxylic compound. In lthejnass polymerizationprocess, the monomeric vinyl aromatic compound and the dicarboxyliccompound are generally heated to temperatures within the range of 40 toC. and maintained at such temperatures :until the major portion of :themonomers have reacted, after which the temperature of the mass ;is,raised to to Cutocomplete the polymerization of theremaim ing-monomers.'Thernass polymerization process is preferably carried out bypolymerizing the monomers in the presence of a small amount ofpolymerization catalyst, particularly a peroxide catalyst such asbenzoyl peroxide. The mass is substantially free .of solvents ordiluents for the monomers. The copolymer is obtained in the form of ahard glassy resin which is preferably comminuted before it :is used.

Another suitable method for preparing the copolymers for use in makingthe choline salt is the so-called soivent-non-solvent process whichinvolves heatinga solution of the vinyl aromatic compound and thedicarboxylic compound in a hydrocarbon liquid which is a solvent for themonomers but -a non-solvent for the copolymer formed by thepolymerization of the monomers. Benzene, tolueneand xylene have beensuccessfully used as thehydrocarbon liquid. The processis preferablycarried out in the presence of a small amountofapolymerizationcatalystparticuljarly a peroxide-catalyst. such as benzoyl peroxide. Thecopolymer precipitates from the by drocarbon liquid in the form of fineparticles as it is formed, and is afterwards separated from thhydrocarbon liquid by filtering or the like and then the hydrocarbonliquid is evaporated from the copolymer solids.

As examples of vinyl aromatic compounds containing a single C==CH2 groupwhich are useful in preparing the copolymers may be mentioned styrene,halogen substituted styrene such -as p-ohloro styrene, dichloro-styreneand the like, and alkyl substituted styrenes such as p-methyl styrene,dimethyl styrene and the like. Styrene is preferred because of its lowcost and availability and superior properties for this partic ularpurpose.

.As examples of ethylene apdicarboxylic compounds which arev useful inpreparing the copolymers may be mentioned .maleic acid, .maleic,anhydride, fumaric acid, citraconic anhydride. itaconic anhydride andthe like and alkyl half esters of the corresponding acids, which contain from 1 to 3 carbon atomsin the alkyl group, for example methyl,ethyl and propyl acid maleate and the corresponding 'fumarates,citraconates and itaconates. When the alkyl acid esters of ethylene (1,5dicarboxylic acids are used it is preferred to use a mixture ofdicarboxylic compounds containing at least '50 mol per cent of anethylene 11,5 dioarboxylic acid or :anhydride, more V spectively. ,1

particularly an anhydride. Maleic anhydride is the preferreddicarboxylic compound because of its low cost and ready availability andits superiority over the other dicarboxylic compounds as a component ofthe copolymer. Mixtures of maleic anhydride and methyl acid maleatecontaining from 99 to 50 mol per cent of maleic anhydride are alsopreferred over the other dicarboxylic compounds or mixtures thereof.

The water solution of choline salts of the copolymer are normally thesole sizing agents used in the practice of this invention. However, insome instances it is possible to use up to 20% by weight of an alkalimetal salt of a styrenemaleic acid copolymer to replace a part of thecholine salt. The water solutions of the choline salt of the copolymergenerally contain from 4 to 35% by weight of the choline salt and have aviscosity between about 50 and 20,000 centipoises at 25 C. depending onthe concentration of the solution, thepH of the solution and theparticular copolymer used in preparing the choline salt. Theviscosity'of the solution may be modified by adding glycerine. viscosityof the solution and this is particularly The glycerine increases thedesirable in some instances where the viscosity of choline salt solutionis too low for sizing purposes. Amounts of 1 to 40% by weight ofglycerine, on the weight of the choline salt, are generally satisfactoryfor this purpose. The glycerine also improves the adhesion of the sizeto I the yarns. The solutions may also contain plasticizers such aspolyethylene or polypropylene glycols and softeners such as Twitchelloil, sulfonated tallow and sulfonated vegetable oil.

However, it is essential that the size solutions be free of reactivesubstances, that is substances which react with the choline salt atnormal drying temperatures to form water-insoluble resins. f

A further understanding of the methods and compositions of thisinvention will be obtained from the following specific examples whichare. intended to illustrate the invention but not to. limit its scope,parts and percentages being by.

weight unless otherwise specified.

Example I One hundred and twenty parts of a finely dividedstyrene-maleic anhydride-methyl acid maleate copolymer (containing 51%of combined styrene, 37.4%" of combined maleic anhydride and 11.4% ofcombined methyl acid maleate) were added to 1188 parts of water at atempera ture of 40 to C. The resulting mixture was well agitated and 192parts of a 40% water solution of choline were added. The mixture washeated to 90 C. and then boiled for one hour to dissolve thecopolymer asthe choline salt. The

' resulting solution had a pH of 7.3 (glass elecof the size between thefilaments in the yarn.

The sized yarns were then dried by passing them over five rotatingdrying cans heated to temperatures of 180, 200, 200, 200 and 160 LFE,re-

. 6 The dry yarns were quite supple and flexible, but yet sufilcientlystiff to handle well in a loom.

They were covered with a tough, elastic coating which adhered to theyarn without dusting when the yarn was quickly stretched and thenimmediately relaxed. After being conditioned for 24 hours at atemperature of 70 F. and a relative humidity of 65%, a number of thesized yarns were broken and the broken ends of the yarns were examined.They were found to be free of loose or fluffy filaments which indicatesthat the size has excellent adhesion to the yarns and also binds theindividual filaments together thus affording maximum protection againstyarn defects during weaving. The yarns had excellent weaving efiiciencywhen woven in a conventional loom, and the size was readily removed fromthe woven fabric by washing the fabric in warm water.

Example II Unsized 70/34/7Z/100 bright polyhexamethylone-adipamide warpyarns were sized with the above solution using the procedure describedin paragraph 2 of Example I. The dry sized yarns were considerablystiffer than those prepared in accordance with the procedure of ExampleI, but were similar to those yarns in weaving eificiency, ease ofremoval of the size and in the adhesion of the size to the individualfilaments of the yarns. 7

Example III A water solution of the choline salt of a copolymer ofstyrene-maleic anhydride-methyl acid maleate was prepared as describedin the first paragraph of Example I and to this was added sufficientglycerine to provide 30% of glycerine on the weight of the copolymer.The solution was diluted with water to 8% solids and at thisconcentration had a pH of 7.3 and a viscosity of 650 centipoises at atemperature of 25 C.

Unsized 70/34/7Z/100 bright polyhexamethylene-adipamide warp yarns weresized with the above solution using the procedure described in paragraph2 of Example I. The dry sized yarns were quite supple and flexible butyet were sufiiciently stiff to handle well in a loom. The size coatingon yarns was tough and elastic and adhered to the yarn without dustingor shedding when the yarn was quickly stretched and immediately relaxed.The yarns had excellent weaving efiiciency and few yarn breaks wereencountered during weaving. Moreover, the woven fabric was substantiallyfree of defects.

Example IV One hundred and twenty parts of a finely diadded to 1188parts of water at a temperature of,

40.1 to. .10 G; The esult n xture was well a itated and. 1.92 nartsof; a40% water so u ion at holine were. added aft r wh h. the-mixt re asboiled for 1,; hour to dissolve the copolymer in the; form, of; its;choline salt. The solution was c oled andsnfficien -chohne; was added toi the. DH; up to 9 .2,- after which sufficient glycerine was; added toprovide 30% of glycerine on the weight of the copolymer in the solution.The, solution Was thendiluted with water until it contained=8;%,copolymer solids and at this concentration hadta viscosity of 26 3centipoisesat 25 C.

Unsized 70/34/7Zr/1OQ bright polyhexameth-ylene-adipamide warp yarnsweresized with the above: solution using the procedure described in aragraph2. of Example 1;... The d y siz d yarns had properties similar to, thoseof the. ized yarns prepared as. described in Example III.

Ex mple V $i QQ1ul I SWB 1 n e a as, described in he. precedin am es x pa a. copolymer oiistyrene-maleie anhydride (containing 52% of combinedstyrene and"48% of combined maleic anhydride-methyl acid maleate). Theresulting solutions were used to size 70/34/72/100 bright unsizedpolyhexamethylene adipamide warp yarns using the procedure described inparagraph 2 of Example I. The resulting sized yarns had propcrti'eswhichwere similar to the corresponding sized yarns of the preceding examples.

Example VI Four hundred and fifty-two parts of a finely dividedstyrene-maleic anhydride-methyl acid maleate copolymer (containing 51%of combined styrene, 37.4% of combined maleic anhydride and 11.4% ofcombined methyl acid maleate) were added rapidly to 2548 parts of aWater solution containing 298 parts of choline at a temperature of C;.The resulting mixture was heated to a temperature of'90 C; over a periodofone hour and then maintained at that temperature for another hour,after which time the copolymer dissolved: in the. formo-- its cholinesalt. The resulting: solution was diluted; with water until it containedl8,%- of the cholinev salt of the copolymer. The pH of this solution was7.44 (glass electrode) and the viscosity was 735 centipoises a t. C;

Seven ends of spun yarn prepared from polyacrylonitril'e staplefiberwere passed at the rate of 15 yardsper minute through the 18%solution of choline salt of the copolymer which was maintained at atemperature of 140 to 150 FL, after which the yarns were squeezed bypassing them between squeeze rolls and applying a pressure or 6.66pounds. per linear inch. About 15% of the cholinesalt was deposited onthe yarn based on the yarn weight. The sized yarns were then dried bypassing them over five rotating drying cans heated to temperatures of180, 200, 200, 200 and 160 F., respectively.

The dry yarns were sufiiciently stiii ened to handle well in a loom andhad excellent weaving efficiency when Woven in a conventional loom.Moreover, the size coating was tough and flexible and had excellentadhesion to the yarn. The size was readily removed from the yarns byWashing the woven fabric in warm water.

The sized" yarns possessed increased tensile strength and excellentabrasion resistance as indicated by the following; tests. A portion ofone of the sized yarns was first conditioned for 24 hours at a relativehumidityof and a temperature of '70 F. and then tested for tensilestrength and; abrasion resistance. A control sam ple of unsized yarn wasconditioned andtested in the same manner. The following table shows theresults obtained.

Indicates number of' cycles required in abrasion resistance testernecessary to break the yarn.

Various modifications and changes may be made in the methods andcompositions set forth in the foregoing description as will be apparentto those skilled in the art to which this invention appertainswithout-departing from the spirit and intent ofthis invention. It is tobe understood therefore that the present invention is to be limited onlyby the scope of the appended claims.

Whatisclaimed is:

1 A method of sizing water-insoluble synthetic linear polymer yarnswhich comprises applying to said yarns a Water solution of a cholinesalt of a copolymer consisting of the copolymerization product of apolymerizable vinyl aromatic compound having a single C=CH2 group and anethylene a, ,8 dicarboxylic compound selected from the group consistingof ethylene a, ,8 dicarboxylic anhydrides, ethylene a, B dicarboxylicacids and partial alkyl esters of said acids having not more than 3carbon atoms in the alkyl group, and mixtures of, said dicarboxyliccompounds, and drying said yarn preparatory to weaving the same.

2. A method oi sizing water-insoluble synthetic linear polymer yarnswhich comprises applying to said yarns a water solution of a cholinesalt of a copclymer consisting of the copolymerizaticn product ofstyrene and maleic anhydride, and drying said yarn preparatory towearing the same.

3. A method of sizing water-insoluble synthetic linear polymer yarnswhich comprises applying to said yarns a Water solution of a cholinesalt of a copolymer consisting of the copolymerization productof styreneand a mixture of maleic anhydride and methyl acid maleate, said mixturecontaining from 50 to 99 mol per cent of maleic anhydride, and dryingsaid yarn preparatory to weaving the same.

4. A method of sizing water-insoluble synthetic linear polyamide yarnswhich comprises applying to said yarns a water solution of a cholinesalt of a copolymer consisting of the copolymerization product of apolymerizable vinyl aromatic compound having a single C=CH2 group and anethylene 02,3 dicarhoxylic compound selected from the group consistingof ethylene 11,5 dicarboxylic anhydrides, ethylene 11, 6 dicarboxylicacids and partial alkyl esters of said acids having not more than 3carbon atoms in the 'alkyl group, and mixtures of said dicarboxyliccompounds, and drying said yarns preparatory to weavingthe same.

5. A method substantially according to claim 4, butfurthercharacterizedin that the synthetic linear polyamide yarns arepolyhexamethylene-adipamide yarns.

6. A method of sizing water-insoluble polyhexamethyl'ene-adipamide yarnswhich comprises applying to said yarns a water solution of a cholinesalt of a copolymer consisting of the copolymerization product ofstyrene and maleic anhydride, said solution being applied in an amountsufiicient to provide from 1 to 15% by weight of said choline salt onthe weight of the yarns, and drying said yarns preparatory to solutioncontains an amount of glycerine sufficient to increase the viscosity ofthe solution over and above the viscosity obtained with the choline saltper se.

8. A method of sizing water-insoluble polyhexamethylene-adipamide yarnswhich comprises applying to said yarns a water solution of a cholinesalt of a copolymer consisting of the copolymerizationproduct of styreneand a mixture of maleic anhydride and methyl acid maleate, said mixturecontaining from 50 to 99 mol per cent of maleic anhydride, said solutionbeing applied in an amount suflicient to provide from 1 to 15% by Weightof said choline salt on the weight of the yarns, and drying said yarnspreparatory to weaving the same.

9. A method substantially according to claim 8, but furthercharacterized in that the water solution contains an amount of glycerinesufficient to increase the viscosity of the solution over and above theviscosity obtained with the choline salt per se.

10. A method of sizing water-insoluble polyacrylonitrile yarns whichcomprises applying to said yarns a water solution of a choline salt of acopolymer consisting of the copolymerization product of a polymerizablevinyl aromatic compound having a single C=CH2 group and an ethylene 11,3 dicarboxylic compound selected from the group consisting of ethylene1,5 dicarboxylic anhydrides, ethylene 1,5 dicarboxylic acids and partialalkyl esters of said acids having not more than 3 carbon atoms in thealkyl group, and mixtures of said carboxylic compounds, said solutionbeing supplied in an amount sufficient to provide from 1 to 15% of saidcholine salt on the weight of the yarns, and drying the yarnspreparatory to weaving the same.

11. A method of sizing water-insoluble polyacrylonitrile yarnssubstantially according to claim 10, but further characterized in thatthe copolymer consists of the copolymerization product of styrene andmaleic anhydride.

12. A method of sizing water-insoluble polyacrylonitrlle yarnssubstantially according to claim 10, but further characterized in thatthe copolymer consists of the copolymerization product of styrene and amixture of maleic anhydride and methyl acid maleate, said mixturecontaining from to 99 mol per cent of maleic anhydride.

13. A choline salt of a copolymer consisting of the copolymerizationproduct of a polymerizable vinyl aromatic compound having a single C=CH2group and an ethylene 11,5 dicarboxylic compound selected from the groupconsisting of the ethylene 11,3 dicarboxylic anhydrides, ethylcm; 11,5dicarboxylic acids and partial alkyl esters of said Iacids having notmore than 3 carbon atoms in the alkyl group and mixtures of saiddicarboxylic compounds.

14. A choline salt of a copoylmer consisting of the copolymerizationproduct of styrene and maleic anhydride.

15. A water solution of a choline salt of a copolymer consisting of thecopolymerization product of styrene and maleic anhydride, said solutioncontaining sufiicient glycerine to increase the viscosity of thesolution over and above the viscosity obtained with the choline salt perse.

16, A choline salt of a copolymer consisting of the copolymerizationproduct of styrene and a mixture of maleic anhydride and methyl acid.maleate, said mixture containing from 50 to 99 mol per cent of maleicanhydride.

17. A water solution of a choline salt of a copolymer consisting of thecopolymerization product of styrene and a mixture of maleic anhydrideand methyl acid maleate, said mixture containing from 50 to 99 mol percent of maleic anhydride, said solution containing suflicient glycerineto increase the viscosity of the solution over and above the viscosityobtained with the choline salt per se.

ELMER H. ROSSIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 351,890 Waite Nov. 2, 18862,286,062 Condo et a1 June 9, 1942 2,469,407 Powers et al. May 10, 1949FOREIGN PATENTS Number Country Date 726,670 Germany Oct. 17, 1942 OTHERREFERENCES Karrer, Organic Chemistry, 2nd ed., pages 234- 235.

1. A METHOD OF SIZING WATER-INSOLUBLE SYNTHETIC LINEAR POLYMER YARNS WHICH COMPRISES APPLYING TO SAID YARNS A WATER SOLUTION OF A CHOLINE SALT OF A COPOLYMER CONSISTING OF THE COPOLYMERIZATION PRODUCT OF A POLYMERIZABLE VINYL AROMATIC COMPOUND HAVING A SINGLE <C=CH2 GROUP AND AN ETHYLENE A, B DICARBOXYLIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF ETHYLENE A, B DICARBOXYLIC ANHYDRIDES, ETHYLENE A, B DICARBOXYLIC ACIDS AND PARTIAL ALKYL ESTERS OF SAID ACIDS HAVING NOT MORE THAN 3 CARBON ATOMS IN THE ALKYL GROUP, AND MIXTURES OF SAID DICARBOXYLIC COMPOUNDS, AND DRYING SAID YARN PREPARATORY TO WEAVING THE SAME. 